Radio receiving system



July 26, 1927. 1,637,045

E. w. K EL LOGG .RADIO RECEIVING SYS'I'BIw Filed April 15, 1922 Receiver IhvenL-orfl Edward W Kel [08%; b WM His'ALLor-ne Patented July 26, 1927. Q

, UNITED STATES PATENT OFFICE.

EDWARD W. KELLOGG, OF SCHENECTADY, NEW YORK, ASSIGNOB T GENERAL ELEC- TRIO COMPANY, A'CORPOBATION OF NEW YORK..

7 name nncnrvmo sys'rnm.

Application filed April 15,

present invention relates to radio receivmg systems and more particularly to an arrangement of antennae which is especially adapted for radio reception.

In my Patent 1,487 ,339, issued March 18, 1924, I have described a unidirectional re ceiving antenna made up of two horizontal conductors and have set forth and claimed a means whereby the antenna conductors may be employed as a transmission line for carrying the signaling currents from the point in the antenna where they are strongest to a distant point along the length of the antenna where the receiving station may be more conveniently located. In this case a transformer is provided at the end otthe antenna where the signaling currents received are strongest and the signaling currents received upon the two conductors of the antenna in parallel are caused to unite and flow through the primer of this transformer. The secondary o the transformer has its terminals connected to the two antenna conductors so that'these two conduotors serve as the two sides of a transmission line which conveys the signaling currents back to the other end of the antenna or to any desired point along its length. In practice the primary winding of the transformer is generally connected between ground and a neutral or mid point of the secondary winding.

The object of my present 1nvent1on is to provide an improvement in the apparatus described whereby the same efiect may be obtained without the use of a transformer.

It has been found in practice that the most suitable ratio to employ for the transformer mentioned is a two to one ratio. This means that the currents impressed upon the transmission line by the transformer will be substantially equal in value to the signaling current received upon each conductor. In onaof the conductors the signaling current thus impressed upon the transmission linewill flow in the same direction as the signalin current received thereon whereas in the other conductor the impressed current will flow in the opposite direction to the signaling current received. The result will be that at the end of the antenna to which the transformer is connected a current of twice the value of the received si aling current will flow in one conductor w 'le the two currents 1922. Serial no. 552,868.

'necting the other conductor to ground through as low a resistance as is obtainable,

thereby producing a short circuit reflection I in that conductor.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, my invention itself, however, both as to its organization and method of operation will best be understood bv reference to the followingdescription taken in connection with the accompanying drawing in which I have illustrated diagrammatically one way in which my invention may e carried into effect. I

As indicated in the drawing, I provide a long antenna made up of two parallel horizontal conductors 1 and 2. Ground'connections are provided at the ends 3 and 4 of this antenna, the ground connection at 3 being made through a resistance 5 having a value substantially equal to the surge impedance of the antenna to prevent undesired reflections back over, the length of the conductors. An antenna of this type has marked unidirectional properties, the signaling current received on the antenna being of maximum value at the end furthest from the transmittin station, and ofminimum value or substantially zero at the end of the antenna nearest the transmitting station. In the present case it is assumed that it is desired to receive signaling waves travelling along the antenna through the ether from ward the end 3. In my prior patent above referred to, I have accomplished this by means of a transformer as described, located at the end 4. In the present case, however, the desired effect may be obtained by open circuiting the end of the conductor 1 at end 4 of the antenna, and directly grounding conductor 2. The result of this arrangement is to produce an open circuit reflection back along the length of the conductor 1, which is superimposed upon the current wave built up on the antenna by the signal in such phase and magnitude as to produce zero current at the end 4 of antenna conductor 1,. At the same time a short circuit reflection is produced in conductor 2, which in effect practically doubles the current flowing in that conductor. Thus the opening of conductor 1 and grounding of conductor 2 produces an effect at the end 4 of the antenna exactly equivalent to the effect obtained by use of a transformer, and the effect on the receiving apparatus 9 will also be the same as though a transformer had been employed at the end 4:.

The winding 6 of transformer 7 is not affected by currents flowing in the same direction in the two conductors of the antenna, but is affected by currents which flow in opposite directions in the two conductors. The signal waves built up on the antenna flow in the same direction in both conductors, but the waves reflected from the end 4 in the manner described in my present invention, flow in opposite directions in con ductors 1- and 2, and therefore affect the receiving set through the transformer 7.

By reason of the resistance in ground connection 4 of the antenna there may be a loss of energ in the short circuit reflection and the re ected current in conductor 2 will be less than that in conductor 1. This unbalance will in some cases be detrimental. The 'difliculty may be overcome by the provision of a leak resistance 10 which may be connected between the end of conductor '1 and ground by means of a switch 11. The resistance of this leak 10 should be approximately such that R zZ: :Z:R in which proportion R is the resistance of the leak 10, B the resistance of the ground, and Z the surge impedance of one conductor with ground return.

\Vhile I have shown and described one simple embodiment of my invention, it will be apparent that manymodiflcations in the manner in which it is applied as well as in the location of the receiving apparatus may be made without departing from the scope of my invention as set forth in the appended claims. The use of this invention elimiconductors system of a long horizontal antenna made up of two parallel conductors, means at one.

end of said antenna for producing an open circuit reflection in one of said conductors and a short circuit reflection in the other and means for combining the reflected currents to operate a receiver.

2. The combination in a radio receiving system of a long horizontal antenna made up of two parallel conductors both of said eing grounded at one end, and one only of said conductors being grounded at the opposite end and means for supplying to a receiving apparatus currents flowing in the two conductors. v

3. The combination in a radio receiving system of a long horizontal antenna made up of two parallel conductors, means at one end of said antenna for producing reflections of different phase in the two conductors and means for combining the reflected cur:

rents to operate a receiver.

4. The combination in a radio receiving system of a long horizontal antenna made up of two parallel conductors, receiving apparatus located at one point along said antenna ,and connected to both of said con ductors and means at another point in said antenna for producing reflections of different phase in the two conductors.

5. The combination in a radio receiving system of a long horizontal antenna made up of two parallel conductors, receiving apparatus located at one point along said antenna and means at another. point in said antenna for transmitting the energy of received slgnals over the two conductors to the re celving apparatus comprising means for producing reflections of different phase in the two conductors.

'6. The combination in a radio receiving system of a long horizontal antenna made up of two parallel conductors and means at one end of the antenna for producing reflections of difl'erent phase over the two conductors and thereby producing a desired efi'ect in recelving apparatus connected across the two conductors at a distant point.

In witness whereof, I have hereunto set my hand this 14th day of April, 1922.

EDWARD w. KELLOGG. 

